Address Spaces

An address space defines a view into memory. It determines how memory objects are addressed and accessed by threads. In Slang, the address space for a variable is determined by its type, modifiers, and attributes. For example, data in ConstantBuffer<T> belongs to the uniform address space, and the address space for a static groupshared variable is group-shared.

The following address spaces are defined:

Address space	Slang construct	Instance scope	Description
Uniform	uniform ConstantBuffer<T>	All threads	Uniform values are parameters of a Slang program. They are expected to remain constant over the lifetime of a launch/dispatch.
Image	Texture1D<...> Texture2D<...> etc.	All threads	Images are multi-dimensional arrays of texels, typically containing color, depth, stencil, and similar data.
Push constant	[push_constant] [vk_push_constant]	All threads	Push constants are small, frequently updated constants passed directly through the command stream. On Vulkan, these correspond to push constants.
Storage buffer	StructuredBuffer<T> RWStructuredBuffer<T>	All threads	Storage buffers are read-only or read-write buffers, typically shared between the host and Slang programs.
Group-shared	static groupshared (global scope)	Thread group	Group-shared variable instances are shared by a thread group.
Function	Function parameters and non-static local variable declarations	Thread	Function parameters and local variables are visible only to the function invocation.
Thread-local	static (global scope)	Thread	Thread-local variables have separate instances per thread.
Input	Entry point input parameters (non-uniform)	Thread	Entry point inputs to a graphics shader stage come from the system and the previous stage.
Output	Entry point output parameters Entry point return value	Thread	Entry point outputs from a graphics shader stage are inputs to the next stage.
Specialization constant	[SpecializationConstant] [vk::specialization_constant]	All threads	Vulkan specialization constants have values that are fixed at pipeline creation time.
Host	None	Host process	The host address space is used by the host program. This is typically the virtual address space of the application process. The host address space is not usually directly accessible by a Slang program, except when the program is compiled for the C++ target.

📝 Remark 1: Address spaces specific to graphics pipeline stages are not enumerated here. See Graphics Shaders and Compute Kernels for a description.

📝 Remark 2: A pointer to memory in one address space is generally not interchangeable with a pointer to memory in another address space. In particular, pointers to group-shared memory are not interchangeable between thread groups.

📝 Remark 3: Address spaces in Slang are roughly equivalent to SPIR-V storage classes.